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V VALVE GEAR FOR STEAM ENGINES.

I No. 257,994. Patented May 16, 1882.

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N, PETERS PhclwLilhcgrapher. Washington. D. c.

, (No Model.) v i 2 Sgeets-Sheet 2. R. W. AITKEN & D. FA RQUHAR.

VALVE GEAR'IEOB, STEAM ENGINES.

No. 257,994. Patented May 16, 1.882.

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UNITED STATES 1 PATENT OFFICE ROBERT W. AITKEN AND DAVID FARQUHAR, or BUFFALO, NEW YORK, ASSIGNORS TO THE rrrrs AGRICULTURAL WORKS, or SAME PLACE.

VALVE-GEAR FOR STEAM-ENGINES.

SPECIFICATION forming part of Letters Patent No. 257,994, dated May 16,1882.

Application filed March 16, 1882.

To all whom it may concern Be it known that we, ROBERT W. AITKEN and D'AViD FARQUHAR, of the city of Buffalo, in the county of Erie and State of New York,

have invented new and useful Improvements .in Valve-Gear for Steam-Engi n es, of which the following is a specification.

The object of this invention is to simplify the operations of adjusting the link of a reversible engine and opening or closing the throtile, so that these operations can be simultaneolisly executed; and our invention consists to that end in connecting the mechanism of the link which controls the motion of the steamvalve with the mechanism for openin g and closing the throttle-valve, to admit steam to or exclude it from the steam-valve, in such a manner that the movement of asingle lever will adjust both the link and the throttle-valve.

()ur invention consists, further, of a drip-' pipe which leads from the valve-chest down to the boiler, and whereby the water which accumulates in the valve-chest is returned to the boiler.

In the accompanying drawings, consisting of two sheets, Figure l is a side elevation, Fig. 2 a top plan view, and Fig. 3 a rear elevation, of the cylinder of a steam-engine provided with ourimprovement. Fig. et'is avertical section, and Fig. 5 a horizontal section, through the chest of the throttle-valve.

Like letters of reference refer to like parts in the several figures.

A represents the steamboiler of a portable or traction engine.

B represents the steam-cylinder, secured in the usual manner to' a frame, B, which is attached to the boiler A.

0 represents the valvechest, in which the slide-valve O operates, which directs the steam to both ends of the cylinder.

0 is the rod of the slide-valve, which projects through a stuffing-box, c, in the front end of the valve-chest, and which is operated by a link, D, and eccentric-rods d d in a wellknown manner.

E represents the reversing-lever, mounted on a horizontal shaft, 6, 'which rocks in standard-bearings f, secured to the valve-chest G.

(No model.)

f represents the guide-segment, provided with notchesgggf, in which a suitable springcatch engages, which is attached to the reversin g-leverEin a well-known manner, and whereby the reversing-lever may be secured in one of several positions.

h represents the short arm of the reversinglever, and h is a rod whereby the link D is suspended from the arm h. may be constructed in any suitable and wellknown manner.

I represents the chest in which the throttlevalve J is arranged, whereby the admission of steam from the boiler to the valve-chest O is regulated.

All of these parts As shown in the drawings, the. throttle-valve chest I communicates with the valve-chest O by means of the governor-casin g K and a tube, K.

L represents. the pipe through whichthe steam is conducted from the dome of the boiler to the throttle-valve chest I,-and Z is a drippipe descending from the bottom of the chest I to the body of the boiler, so as toform an ontletfor the water of condensation which may collect in the chest I, and which is returned by the pipe I to the boiler.

m represents the rod by which the throttlevalve J is operated, and which projects through a stuffing-box,m,in the front end of the valve chest I, and is attached to an arm, a, which is secured to the rod-shaft e of the reversinglever E, so that by moving the latter in one or the other direction, both the link D and the throttle-valve J are moved simultaneously.

The arm n is so arranged with reference to the reversing-lever E and the valve J that the latter will be in its central position and cover its port 0, as shown in Figs. 4 and 5, when the reversing-lever E is in its central position or on the stopping-point, as shown in Fig. 1, in

which the link D does not operate the main sut'ficientlyto admit steam to the the valve-chest 0.. The extent to which the port 0 is opened will be greater or less according to the distance to which the reversing-lever is moved out of its central position, so that the degree of expansion given by the link and the quantity of steam admitted to the cylinder by the throttle-valve will be regulated simultaneously and in an inverse ratio by simply adjusting the reversing-lever.

When the reversing-lever is in the central position the throttle-valve J is closed, and the steam-pressure is thereby removed from the steam-valve G. The reversing-lever can therefore be moved easily out of its central position either toward the forward notch, g, or backward notch, 9 The engine is also readily reversed, because the throttle-valve J will be closed or only slightly opened during a large portion of themovement of the reversing-lever as it approaches its central position and recedes therefrom.

By connecting the throttle-valve with the reversing-lever, as described, thedirection in which the en gine-shaf t is rotated and the admission of steam to the cylinder or the shuting off of the steam are regulated by simply moving the reversing-lever, which latter is readily operated with one hand, leaving the other hand of the engineer free to operate the steering mechanism, it the apparatus is applied to a traction-engine.

Upon placing the reversing-lever in the central position or on the stopping-point, the throttle-valve J is closed at the same time, and the steam contained in the passages between the throttle-valve and the cylinder is confined and enters both ends of the cylinder, whereby a steam cushion is formed in the cylinder in front of the piston, which prevents the piston from stopping at the end of its stroke, and the crank on its dead-center, thereby facilitating the starting of the engine.

We claim as our invention 1. In a reversible steam-engine, the combination of a steam-distributing valve adapted to be operated forward and backward, a throttle-valve whereby the admission of steam to the steam-distributin g valve is controlled, and mechanism whereby the motion of the steam distributing valve and the position of the throttle-valve are controlled simultaneously, substantially as set forth.

2. The combination, with the link D, where.- by the motion of the steam-distributing valve is controlled, and a throttle-valve, J, whereby the admission of steam to the distributingvalve is regulated, of a reversing-lever, E, connected with the link D and the valve J, whereby both are adjusted simultaneously, substan-. tially as set forth.

3. The combination, with the steam-valve O and the throttle-valve J, of the link D, connected with the valve 0, the reversing-lever E, mounted on a rock-shaft, e, and connected with the link D, and an arm, a, secured to the shaft e and connected with the throttle-valve J, substantially as set forth.

4. The combination of a valve-chest, I, con:- nected with the steam-boiler by a pipe, L, and adrip-pipe, Z, which descends from the valvechest to the steam-boiler, and whereby the water of condensation is returned to the boiler, substantially as set forth.

ROBERT W. AITKEN.

- DAVID FARQUHAR.

Witnesses:

JNo. J. BONNER, OHAs. F. GEYER. 

